NASA's Spitzer Space Telescope discovered an enormous ring around Saturn -- by far the largest of the giant planet's many rings. The belt lies at the far reaches of the Saturnian system, with an orbit tilted 27 degrees from the main ring plane. The bulk of its material starts about six million kilometers (3.7 million miles) away from the planet and extends outward roughly another 12 million kilometers (7.4 million miles). One of Saturn's farthest moons, Phoebe, circles within the newfound ring, and is likely the source of its material.

Saturn's newest halo is thick, too -- its vertical height is about 20 times the diameter of the planet. It would take about one billion Earths stacked together to fill the ring.

"This is one supersized ring," said Anne Verbiscer, an astronomer at the University of Virginia, Charlottesville. "If you could see the ring, it would span the width of two full moons' worth of sky, one on either side of Saturn."

The ring itself is tenuous, made up of a thin array of ice and dust particles. Spitzer's infrared eyes were able to spot the glow of the band's cool dust. The telescope, launched in 2003, is currently 107 million kilometers (66 million miles) from Earth in orbit around the sun.

The discovery may help solve an age-old riddle of one of Saturn's moons. Iapetus has a strange appearance -- one side is bright and the other is really dark, in a pattern that resembles the yin-yang symbol. The astronomer Giovanni Cassini first spotted the moon in 1671, and years later figured out it has a dark side, now named Cassini Regio in his honor. A stunning picture of Iapetus taken by NASA's Cassini spacecraft is online http://photojournal.jpl.nasa.gov/catalog/PIA08384 .

Saturn's newest addition could explain how Cassini Regio came to be. The ring is circling in the same direction as Phoebe, while Iapetus, the other rings and most of Saturn's moons are all going the opposite way. According to the scientists, some of the dark and dusty material from the outer ring moves inward toward Iapetus, slamming the icy moon like bugs on a windshield.

"Astronomers have long suspected that there is a connection between Saturn's outer moon Phoebe and the dark material on Iapetus," said Hamilton. "This new ring provides convincing evidence of that relationship."

The ring would be difficult to see with visible-light telescopes. Its particles are diffuse and may even extend beyond the bulk of the ring material all the way in to Saturn and all the way out to interplanetary space. The relatively small numbers of particles in the ring wouldn't reflect much visible light, especially out at Saturn where sunlight is weak.

"The particles are so far apart that if you were to stand in the ring, you wouldn't even know it," said Verbiscer.

Spitzer was able to sense the glow of the cool dust, which is only about 80 Kelvin (minus 316 degrees Fahrenheit). Cool objects shine with infrared, or thermal radiation; for example, even a cup of ice cream is blazing with infrared light. "By focusing on the glow of the ring's cool dust, Spitzer made it easy to find," said Verbiscer.

As Cassini scientists await the data from today’s flyby of Enceladus, images and data from August of this year have provided more insight into the active fissures on the icy moon’s south polar region. These geyser-spewing fractures are warmer and more complicated than previously thought.

“The exquisite resolution obtained on one segment of the Damascus fracture — one of the most active regions within the south polar terrain — has revealed a surface temperature reaching a staggering 190 Kelvin, or 120 degrees below zero Fahrenheit,” said Cassini imaging team lead Carolyn Porco, in an email announcing the new images. “Far from the fractures, the temperature of the south polar terrain dips as low as 52 Kelvin, or 365 degrees below zero Fahrenheit.”

Porco said that what this means is that a phenomenal amount of heat is emerging from the fractures which are “undoubtedly the result of the tidal flexing of Enceladus brought about by its orbital resonance with Dione. However, details of this heating process are still unclear and are being studied at this very moment.”

By way of comparison, Antarctica at it's coldest is about -120F. However, these kinds of surface temperatures at the distance of Saturn is pretty special.

PASADENA, Calif. -- NASA's Cassini spacecraft has discovered the best evidence yet for a large-scale saltwater reservoir beneath the icy crust of Saturn's moon Enceladus. The data came from the spacecraft's direct analysis of salt-rich ice grains close to the jets ejected from the moon.

Data from Cassini's cosmic dust analyzer show the grains expelled from fissures, known as tiger stripes, are relatively small and predominantly low in salt far away from the moon. But closer to the moon's surface, Cassini found that relatively large grains rich with sodium and potassium dominate the plumes. The salt-rich particles have an "ocean-like" composition and indicate that most, if not all, of the expelled ice and water vapor comes from the evaporation of liquid salt water. The findings appear in this week's issue of the journal Nature.

"There currently is no plausible way to produce a steady outflow of salt-rich grains from solid ice across all the tiger stripes other than salt water under Enceladus's icy surface," said Frank Postberg, a Cassini team scientist at the University of Heidelberg, Germany, and the lead author on the paper. When water freezes, the salt is squeezed out, leaving pure water ice behind. If the plumes emanated from ice, they should have very little salt in them.

Saturn’s curious moon Phoebe features a heavily-cratered shape and orbits the ringed planet backwards at a considerable distance of over 8 million miles (12.8 million km). According to recent news from the Cassini mission Phoebe may actually be a Kuiper Belt object, having more in common with planets than it does with any of Saturn’s other satellites.

132 miles (212 km) in diameter, Phoebe is the largest of Saturn’s irregular moons — a cloud of small, rocky worlds held in distant orbits at highly inclined paths. Its backwards (retrograde) motion around Saturn and dense composition are dead giveaways that it didn’t form in situ within the Saturnian system, but rather was captured at some point when it strayed too close to the gas giant.

In fact it’s now thought that Phoebe may be a remnant from the formation of the Solar System — a planetesimal — with its own unique history predating its adoption into Saturn’s extended family of moons.